fix(app): add missing i18n keys for host settings (#1478)

* fix(app): add missing i18n keys for host settings

The client UI i18n migration (#1282) referenced translation keys that
were never added to any locale file, so i18next rendered the raw key
string in Settings → Host (e.g. a button labeled
"settings.host.daemon.restart.confirm").

Add the six missing keys to all six locales with real translations:
- settings.host.daemon.rename.submit
- settings.host.daemon.restart.confirm
- settings.host.orchestration.systemPrompt.{edit,reset,save,saving}

The seventh broken reference, in pair-device-modal.tsx, used the wrong
namespace (settings.integrations.pairDevices.rowTitle); the key is
defined at settings.host.pairDevices.rowTitle. Point the reference there.

Reported in https://github.com/getpaseo/paseo/pull/1282#issuecomment-4686672699

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* fix(app): correct machine-translated Save/Saving labels (es/fr/ar)

#1282 left several Save/Saving labels machine-translated into the
"economize money" sense rather than the persist-data sense, so users saw
"Ahorro..." (es), "Économie..." (fr), and "توفير..." (ar) where "Saving..."
was meant.

Fix renameModal.saving and settings.project.actions.{save,saving} in the
three affected locales. ar's actions.save also moves from the conjugated
"يحفظ" to the standard button form "حفظ". Wording matches each locale's
already-correct siblings (e.g. es "Proyecto guardado") and the keys added
in the previous commit. ru and zh-CN were already correct and are untouched.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

packages/app/src/desktop/components/pair-device-modal.tsx

@@ -14,7 +14,7 @@ const SNAP_POINTS: string[] = ["82%", "94%"];
 export function PairDeviceModal({ visible, onClose, testID }: PairDeviceModalProps) {
   const { t } = useTranslation();
   const header = useMemo<SheetHeader>(
-    () => ({ title: t("settings.integrations.pairDevices.rowTitle") }),
+    () => ({ title: t("settings.host.pairDevices.rowTitle") }),
     [t],
   );